1. Field of the Invention
This invention relates to a technique for removing a residue generated by, for example, etching in a process for preparing a semiconductor device comprising a low-dielectric-constant film.
2. Description of the Related Art
Recently, in response to requirement for operation of a semiconductor device at a higher speed, a copper with a lower resistance has been used as an interconnection material while in the light of reducing a parasitic capacitance between interconnections, a so-called low-dielectric-constant film has been employed as an interlayer insulating film material. The term “low-dielectric-constant film” refers to a film made of a material having a lower dielectric constant than SiO2, generally a film with a specific dielectric constant of 4 or less.
There have been intense attempts for developing utilities of a film formed by an application process such as HSQ (hydrogen silsesqueoxane) or MSQ (methyl silsesqueoxane) as a low-dielectric-constant film as described above. However, for such a film, the film may be partially dissolved due to moisture absorption during a semiconductor process, or a stress may be generated in the film by heating, leading to, defective interlayer adhesiveness.
Thus, there have been conducted intense application studies for a low-dielectric-constant film formed by CVD. Among others, SiOC exhibits a relatively stable specific dielectric constant (about 2.8) even after a high-temperature process, and is therefore promising as an interlayer insulating film material for a semiconductor device comprising copper interconnections.